These formatted route paths can be accessed easily using url_for and then
format option:

=link_to'admin show page',url_for(:admin,show,:id=>25,:format=>:js)=link_to'admin other page',url_for(:admin,index,:id=>25,:name=>:foo)=link_to'other json',url(:admin,index,:id=>25,:name=>:foo,:format=>:json)